In conventional photolithography, a photoresist is exposed to light through a lithographic mask. The photoresist is modified by the exposure in such a way that either the exposed or unexposed portions of the resist can be removed during subsequent development. Any photolithographic process has limitations, whereby there is a critical dimension below which features are too fine to be resolved. That resolution limit is a critical barrier in reducing the scale of integrated circuit devices such that additional process steps are needed to form the desired features. Self-Aligned Double Patterning (SADP) schemes use precise coatings deposited as “spacers” on the sidewalls of mandrels made from developed photoresist or a sacrificial material at a given pitch, such that after selective mandrel etching the spacers pitch-split.